The upper section of a vehicle body is covered by a roof panel. One of existing technologies related to a vehicle upper body structure that supports a roof panel is described in Japanese Unexamined Patent Application Publication No. 64-56280.
In the vehicle upper body structure described in Japanese Unexamined Patent Application Publication No. 64-56280, a roof arch that supports the roof panel extends laterally between both sides of the vehicle body. The roof panel is supported by the roof arch that is joined to the lower surface of the roof panel, which extends between both ends of the vehicle in the vehicle width direction.
In the case of snow fall, the snow may pile up on the top surface of the roof panel. Accordingly, the upper section of the vehicle body needs to have a sufficient strength for the load due to, for example, snow.